federal investigators are helping police with a fire they say was intentionally set to destroy the law offices of ozzie davis. it started early yesterday morning in vallejo. sergio quintana has the details. >> the inside of the mayor's offices is burned out shell of melted machines and crime scene tape. this is fire that is vicious. >> we expect it's arson and we characterizing as form of domestic terrorism. we have involved the f.b.i. >> we with able to get the first look inside as cleanup crews were sifting through the damage. the mayor was still shaken by the fire and didn't want to say much. >> what is your feeling about this? >> i'm not going to express my feeling. going through the investigation and piece together the pieces and we'll deal with what we have to deal with. >> fire teams were able to quickly knock the flames down when they arrived. >> inside the office, front door and waiting area had been sealed off with crime scene tape. investigators say this is where the fire started, but they have not yet said how it started. now friends of the mayor are speculating about why t